The Finn, whose retired predecessor and 2016 world champion Nico Rosberg paid a flying visit during the morning session, completed 75 laps with a best time of 1 minute 19.705 seconds on ultra-soft tyres.

That was a significant step up from the 1:20.960 set by Ferrari's Kimi Raikkonen on soft tyres on Tuesday, which had ranked as the fastest of the opening 2017 test.

It also offered further evidence of how much quicker the new, wider cars are with their more aggressive aerodynamics and fatter tyres.

The fastest time in 2016 Barcelona testing was 1:22.765.

Australian Daniel Ricciardo was second-fastest for Red Bull, 1.448 seconds slower. Renault's Jolyon Palmer was third with a best lap set on softs. - REUTERS